1. Field of the Invention
The present invention relates to a method for checking the functionality of at least one injector, a device for checking the functionality of at least one injector, a computer program and a computer program product.
2. Description of Related Art
Due to the increasing complexity of the systems and components used in vehicles, a great diagnostic depth is required in combination with rapid and successful troubleshooting at service shops. For example, fuel injection systems and also air systems and exhaust gas systems of vehicles are increasingly tested and/or checked there.
So-called injectors are used for injecting fuel into the internal combustion engine in the case of diesel engines. Because of wear, such injectors may begin to leak at the injection nozzle, allowing fuel to enter the combustion chamber in an uncontrolled manner. This leakage usually occurs only at certain operating points of the injector.
To monitor and regulate, during operation, internal combustion engines used in motor vehicles, so-called lambda sensors are among the sensors used, contributing toward an improvement in the exhaust gas quality of motor vehicles. Such sensors are based on known electrochemical measurement of the oxygen concentration in the exhaust gas.
A method for monitoring a fuel metering system of an internal combustion engine, in particular of a common rail system, is known from published German patent application document DE 196 20 038 A1. In this case, a defect in the fuel metering system is detected when a signal supplied by a sensor for an exhaust gas composition deviates from a preselectable value. The sensor may supply a signal which depends on the oxygen concentration in the exhaust gas. The defect is detected when the signal for the exhaust gas composition deviates from a preselectable threshold.